Senior Kolkata Police officers said the liquor was supplied at outlets in Jain Kunj off Hyde Road, on Saturday night and its effect started showing early next morning.

Deputy Commissioner (Detective Department) Jawed Shamim, who led a house-to-house search to round up country liquor sellers in the area, said a man and three women have been detained for selling the spurious liquor.

Investigations are on to ascertain the source of the liquor. "Samples have been sent for forensic tests," he said. "The interrogation should provide us with necessary leads. Raids are on in the area, and will continue through the night," he added. "According to preliminary investigation, the liquor could be from Poilan," said a senior police officer. All illicit hooch outlets in Kidderpore closed after news of the tragedy spread.